}
    }

    /**
     *  Use an XPath string to select a nodelist.
     *  XPath namespace prefixes are resolved from the contextNode.
     *
     *  @param contextNode The node to start searching from.
     *  @param expression A valid XPath string.
     *  @return A XPathNodes, should never be null.
     *
     * @throws XPathExpressionException if an XPath expression error occurs.
     */

            handlers.setHandlers(new Handler[] { request_handler, new DefaultHandler() });
            server.setHandler(handlers);
        }

        public void start() {
            try {
                server.start();
            } catch (final Exception e) {
                throw new CrawlerSystemException(e);
            }
        }

        public void stop() {
            try {

 * Each enum constant represents a specific event or state in the crawler's execution.
 */
public enum LogType {
    /** Indicates the start of a crawling process. */
    START_CRAWLING,
    /** Indicates the cleanup phase of crawling. */
    CLEANUP_CRAWLING,
    /** Indicates an unsupported URL was encountered when crawling started. */

        }
    }

    public void test_execute_2instanceTx() throws Exception {
        final CrawlerWebServer server1 = new CrawlerWebServer(7070);
        server1.start();
        final CrawlerWebServer server2 = new CrawlerWebServer(7071);
        server2.start();

        final String url1 = "http://localhost:7070/";
        final String url2 = "http://localhost:7071/";
        try {
            final int maxCount = 10;

        handlers.setHandlers(new Handler[] { resource_handler, new DefaultHandler() });
        server.setHandler(handlers);
    }

    public void start() {
        try {
            server.start();
        } catch (final Exception e) {
            throw new CrawlerSystemException(e);
        }
    }

    public void stop() {
        try {
            server.stop();

        handlers.setHandlers(new Handler[] { resource_handler, new DefaultHandler() });
        server.setHandler(handlers);
    }

    public void start() {
        try {
            server.start();
        } catch (final Exception e) {
            throw new CrawlerSystemException(e);
        }
    }

    public void stop() {
        try {
            server.stop();

        handlers.setHandlers(new Handler[] { resource_handler, new DefaultHandler() });
        server.setHandler(handlers);
    }

    public void start() {
        try {
            server.start();
        } catch (final Exception e) {
            throw new CrawlerSystemException(e);
        }
    }

    public void stop() {
        try {
            server.stop();

    }

    /**
     * Reads up to len bytes of data from the input stream into an array of bytes.
     *
     * @param b the buffer into which the data is read
     * @param off the start offset in array b at which the data is written
     * @param len the maximum number of bytes to read
     * @return the total number of bytes read into the buffer, or -1 if there is no more data

        this.listener = listener;
    }

    /**
     * Interface for listening to request lifecycle events.
     */
    public interface RequestListener {

        /**
         * Called when a request starts.
         *
         * @param client the fault-tolerant client
         * @param request the request data
         */
        void onRequestStart(FaultTolerantClient client, RequestData request);

        /**